Incendiary comprising naphthalene and Mg-tetrafluoroethylene

ABSTRACT

A pressed composition of naphthalene and magnesium-Teflon powder is used as an incendiary bomblet fuel.

Simpson et al.

INCENDIARY COMPRISING NAPHTHALENE AND MG-TETRAFLUOROETHYLENE Inventors:Willard F. Simpson; John N. Sichra,

U.S. Cl. 149/2; 102/6; 149/87 Int. Cl F24j 1/04; F42b 25/14 Field ofSearch 102/6; 149/2, 87

[ May 6, 1975 [56] References Cited UNITED STATES PATENTS 3,669,0206/1972 Waite et al. 102/6 Primary Examiner-Leland A. Sebastian Attorney,Agent, or FirmR. S. Sciascia; Roy Miller; LLoyd E. K. Pohl [57] ABSTRACTA pressed composition of naphthalene and magnesium-Teflon powder is usedas an incendiary bomblet fuel.

4 Claims, No Drawings 1 INCENDIARY COMPRISING NAPHTHALENE ANDMG-TETRAFLUOROETHYLENE BACKGROUND OF THE INVENTION 1. Field of theinvention This invention relates to incendiary compositions for use injetting incendiary bomblets and a method for the preparation thereof.

2. Description of the Prior Art letting incendiary bomblets, i.e.,incendiary bomblets which extend their effective range by producingjetting flames when activated, are well known. Such bomblets ordinarilycontain a pyrotechnic composition which releases great quantities ofheat and gaseous combustion products when burning and are provided withjet ports (holes) through which flames jet when the composition isignited.

In the design of jetting incendiary bomblets, several factors must betaken into consideration. The bomblets must be of a size and shape torender them effective when interacting with target types of interest.The material which burns to produce the jetting flames must be safe tohandle in manufacturing processes and yet be easily ignitable. Thematerial must also burn in a manner whereby satisfactory jetting flamesare produced. (That is, flames of sufficient size and temperature toignite the target must be produced.) And, once it is ignited, thematerial should preferably be completely consumed and burn in a mannerwhereby clogging of the jet ports and, thereby, disruption of theworking of the bomblet is avoided.

Prior art materials have been selected because of their ability to meetthe standards suggested by the above factors. And, prior art materialshave been highly satisfactory. However, in the broad field of weaponresearch, the search is continually on for new materials which might dothe job better or do an equally good job less expensively. And, whensuitable new materials are found, methods for the manufacture ofarticles using them must be developed.

SUMMARY OF THE INVENTION It has now been found that certain pressedmixtures of naphthalene and magnesium-Teflon(magnesiumpolytetrafluoroethylene) powder burn in a manner such thatthey are equal or superior to prior art jetting incendiary materials.The pressed compositions disclosed herein are safer to handle thanmagnesium- Teflon which does not have naphthalene added, easily ignited,burn cleanly and, as will be seen from the following discussion, producehighly satisfactory jetting flames.

DESCRlPTlON OF THE PREFERRED EMBODIMENT The preferred jetting incendiarycomposition according to this invention is a pressed grain containing3parts by weight naphthalene and 1 part by weight Magnesium-Teflonpowder.

Magnesium-Teflon is used, in the present invention, for two purposes. Itheats the naphthalene to create a gaseous fuel and it results in thegeneration of pressure which expels the naphthalene fuel through theports of the incendiary bomblet. The naphthalene fuel then burns when itcontacts oxgen present in the atmosphere outside the bomblet. Othercompositions containing differing ratios of naphthalene toMagnesium-Teflon may be used to alter the burning properties of themixture and thus control the incendiary action. The naphthalene used maybe either flake or powder.

The pressed compositions of this invention are prepared either byplacing the mixture of materials in a bomblet casing or in a mold havingthe size and shape of the bomblet casing to be used, or a segment orportion thereof, and applying a pressure of from about 5,000 psi toabout 8,000 psi for a duration of from about 10 seconds to about 30seconds.

in the case where the bomblet casing itself is used as the mold, a covermay simply be placed on the casing after the pressing step is finished.In the case where a mold of suitable size and shape is used the pressedgrain can be easily removed from the mold and placed in a casing of likesize and shape.

As is well known, magnesium-Teflon powder is actually a powder made upof magnesium particles and polytetrafluoroethylene (Teflon) particlesencased in a binder material such as motor oil, Viton A, Vitel, etc..Magnesium-Teflon powder is so well known and so commonly used that itneeds no further explanation here.

As is also well known, naphthalene is a solid at room temperature andremains a solid at temperatures considerably thereabove. Thus, thegrains can be prepared at room temperature. Naphthalene comes from itsmanufacturers in both powder and flake form. Either is suitable for usein the practice of this invention.

A 3 to 1 weight ratio of naphthalene to Magnesium- Teflon has been foundto be greatly preferred. ln tests comparing pressed grains prepared from3 parts by weight naphthalene and 1 part by weight magnesium Teflon topressed grains prepared from 4 parts by weight naphthalene and 1 part byweight magnesium- Teflon and to pressed grains prepared from 2 to 1weight ratio mixtures of naphthalene and magnesium- Teflon, it was foundthat the 3 to l weight ratio grains were superior. They were superior inthat the jets produced a higher temperature as witnessed by the factthat 3 to 1 jets ignited wooden ammunition boxes placed 12 and 18 inchesaway from the jet port whereas the 4 to 1 jets and the 2 to l jets wouldnot. They were superior in that the 3 to l grains burned almostcompletely leaving only about 5% or less unburned material whereas boththe 4 to l grains and 2 to l grains left from ID to 20% unburnedmaterial. They were superior in that no clogging of jet ports wasobserved when the 3 to l grains were burned as opposed to some cloggingin cases where the 4 to l and 2 to 1 grains were used.

in other tests, grains were prepared both by the press ing methoddescribed above and by a slurry method wherein a solution of naphthalenein alcohol was mixed with magnesium-Teflon and the alcohol was allowedto evaporate. The grains prepared by the pressing method were superiorin that they produced jets which would ignite wooden targets from l2 to18 inches away from the jet ports and in only one case out of 10bomblets did the grains fabricated by the slurry method ignite woodentargets placed at like distances from the jet ports.

In still other tests, grains containing 3 parts by weight naphthaleneand lpart weight magnesium-Teflon and prepared by the pressing methoddescribed above were compared with state of the art grains of othermagnesium-Teflon mixtures and with state of the art Alcast grains Thegrains of this invention were found to be superior to state of the artmagnesium-Teflon grains and equal to Alcast grains insofar as targetignition was concerned.

One particularly desirable feature about the compositions of thisinvention is the fact that they can be pressed into almost any desiredshape, This renders them suitable for use in any size or shape ofcontainer ordinarily used for jetting incendiary purposes of which thereare many That is, any continer built to contain a solid grain, providedwith means for igniting the grain and provided with jet ports mayutilize the compositions of this invention. ln the above-describedtests, canisters about 6 inches long and about 2 inches in diameterwhich were provided with a plurality of 9/32 inch diameter jet portsnear one end were used to contain the grains. MagnesiumTeflon rods about1 inch long and one-half inch in diameter were used to ignite thegrains. It should be realized that with containers of different sizesthan the ones used in the tests. different weight ratios of naphthaleneto magnesium-Teflon may turn out to be preferable over the 3 to 1 ratiodescribed herein We claim:

1. An article of manufacture fabricated by pressing a mixture consistingessentially of naphthalene and of magnesium-polytetrafluoroethylenepowder into a suitable shape.

2. An article according to claim 1 wherein 3 parts by weight ofnaphthalene are provided for every 1 part by weight ofmagnesium-polytetrafluoroethylene.

3. A method for manufacturing an article of manufacture, said methodcomprising the steps of:

a. mixing about 3 parts by weight of naphthalene and 1 part by weight ofmagnesium-polytetrafluoroethylene particle in a container having asuitable shape; and

bi pressing said mixture at a pressure of from about 5,000 psi to about8,000 psi.

4. In the method for starting a fire which comprises depositing ajetting incendiary bomblet in an area where ignitable materials arelikely to be and activating a material within the bomblet to producejetting flames the improvement which comprises utilizing a pressed grainof naphthalene and magnesium-polytetrafluoroethylene as said material.

1. AN ARTICLE OF MANUFACTURE FABRICATE DBY PRESSING A MIXTURE CONSISTINGESSENTIALLY OF NAPTHALENE AND OF MAGNESIUMPOLYTETRAFLUOROETHYLENE POWDERINTO A SUITABLE SHAPE.
 2. An article according to claim 1 wherein 3parts by weight of naphthalene are provided for every 1 part by weightof magnesium-polytetrafluoroethylene.
 3. A method for manufacturing anarticle of manufacture, said method comprising the steps of: a. mixingabout 3 parts by weight of naphthalene and 1 part by weight ofmagnesium-polytetrafluoroethylene particle in a container having asuitable shape; and b. pressing said mixture at a pressure of from about5,000 psi to about 8,000 psi.
 4. In the method for starting a fire whichcomprises depositing a jetting incendiary bomblet in an area whereignitable materials are likely to be and activating a material withinthe bomblet to produce jetting flames the improvement which comprisesutilizing a pressed grain of naphthalene andmagnesium-polytetrafluoroethylene as said material.